This invention relates to a method and apparatus for assisting layout design, and particularly to a method and apparatus for assisting layout design suitable for modifying the layout of objects during the layout design process.
For the layout planning of plant installations (equipment and piping), there has been developed a method of automatically determining the optimal piping route by entering data of installation layout and data of design reference, as disclosed in Japanese Patent Kokai JP-A-No. 60-79470. This method, however, does not include the determination of layout for equipment and does not have the ability of modifying the equipment layout plan and existing pipe route for reducing the total pipe length.
A method of assisting layout modification is described in Japanese Patent Kokai JP-A-No. 58-114264. This method is pertinent to the design of printed wiring boards and the layout of IC modules on a printed wiring board, in which a flag indicative of the design procedure is appended to each circuit component and when a circuit component is intended to relocate, the layout plan portion which has been made latter than the circuit component is deleted automatically. The method, however, solely follows the order of component placement, and therefore it does not allow the layout alteration for a high-order layout component in connection with the layout alteration of a low-order layout component.
A hierarchical layout method is proposed in the gazette of Information Processing Society of Japan, Vol. 25, No. 10, 1984, pp. 1080-1081. This method implements first the block layout, next the cell layout within each block, and finally the wiring among cells. The method allows the layout modification within each stage of layout design, however, it is not possible to alter a high-order block layout in order to modify a low-order wiring.
Some of the above-mentioned prior art systems include a layout modification ability, however, they do not reveal which object should be relocated to achieve economical layout.